Learn Variables and Data Types Python Program

Learn Python Variables and Data Types

Variables and Data Types learn Python Program

In this material you will learn about variables and data types in Python Program. Make sure before you already know how to create a script or program in Python programs.

Variables and Data Type Definition: A variable is a place to store data, whereas the data type is the type of data stored in a variable.


Variables and Data Types

Variables are mutable, which means that its value can fluctuate.

Creating Variables in Python Program

Variables in Python programs can be created with the following format:
variable_name = <value>
Example:
variabel_me= "The contents of the variable" 
variabelsecond= 2

Then to see the contents of a variable, you can use the print function.
print variabel_me 
print variabelsecond

Writing Rules Variables

The variable name may not begin to use letters or an underscore (_), for example: name, _name, my name, variable_name.

Subsequent characters can be letters, underscores (_) or number, for example: __name, n2, value1.

Characters on sensitive variable name ( case-sensitive ). This means uppercase and lowercase letters are distinguished. For example, variabel_Me and variabel_me , both are different variables.

The variable name can not use keywords that are already in a Python program like if, while, for, and so on.

Deleting Variables

When a variable is no longer needed, then you can remove the function del ().

Example:
>>> name = "fajaryusuf.com"
>>> print name
fajaryusuf.com
>>> del(name)
>>> print name
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'name' is not defined
>>>
At last command, you will get NameError. This means that the variable is not in memory alias has been deleted.

This type of data

How to fill the variable's value is determined by the type of data, eg for data type text (string), then it must be enclosed in double quotes ( "..."). As for the number (integer) and boolean does not need to be enclosed in quotation marks.

Example:
name_me = "Fajaryusuf.com" 
age = 25 
height = 170.14
Python programs would be to automatically recognize the type of data or types of data stored in a variable.

To check the data type of a variable, you can use the function type ().

Example:
>>> age= 25
>>> type(age)
<type 'int'>
>>> age= "25"
>>> type(age)
<type 'str'>
>>> age= '25'
>>> type(age)
<type 'str'>
>>> age= 25.5
>>> type(age)
<type 'float'>
>>> age= true
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'true' is not defined
>>> age= True
>>> type(age)
<type 'bool'>

Types of Data Types

In general, primitive data types in Python program is divided into three types:

  • Numeric type
  • Text type data
  • Boolean type data 

Let's discuss them one by one ...

1.) Numeric Data Types
Number data types are divided into several types anymore:
int (integer): integer, example : 32, 22, 12, 10, etc. 
float: fractions, for example 1.3, 4.2, 22.3, etc.

Example:
price = 12000 #tipe int
weight = 23:12 #float 
distance = 3E3 #float 3000.0, the letter E means exponent 10

2.) Data Type Text
Text data type again divided into two types:
Char: character, example : 'F'. 
String: set of characters, example "I no longer eat".
Writing text data type must be enclosed in quotation marks. Can use single quotes ( '...'), double quotes ( "..."), and three ( '' '...' '' or "" "..." "").

Example:
name = "Fajar" 
gender = 'L' 
address = "" " 
    Jl. Bendungan, No. 22 RT 02/06, 
    Village Cilodong, Depok 
" "" 
religion = 'Islam'

3.) The data type boolean
Boolean data type is a data type that has only two values: True and False or 0 and 1.

Writing True and False, its first letter should be capitalized and without quotation marks.

Example:
move = True 
flame = 1 #acctualy the type int, but could also be a bool

Sample Program Using Variables and Data Types

Here is a simple example of the application of a variable in the program:
# Python bio population data program
# creates variables and their values
name = "Fajar Yusuf"
address = 'Depok'
age = 25
height = 170.5
married = False
# print variable contents
print "Name:", name
print "Address:", address
print "Age:", age
print "Height:", high
if (married):
     print "Status: married"
else:
     print "Status: not married"


Converting Data Types

Although Python program has been automatically detect the type of data stored in a variable, but there are times when you need to convert data types.

For example, in the following examples:
a = 10
b = 3
c = a / b
print c #output: 3

The division of the value of a and b produces 3 (integer). Why is that?

Because the value of a and b integer, then the result would be an integer.

How to keep the results are there coma?

Of course you have to change the type of variables a and b into fractions (float) first, and only after it is divided. 

as follows :
a = 10
b = 3
c = float(a) / float(b) #output: 3.3333333333333335
print c
Float function () will change the values ​​of a and b being 10.0 to 3.0.


Functions to change the data type:


  • int (): to convert into an integer;
  • Long (): to turn into a long integer;
  • float (): to transform into a float;
  • bool (): to transform into a boolean;
  • chr (): to transform into a character;
  • str (): to convert to a string.
  • bin (): to transform into a binary number.
  • hex (): to transform into hexadecimal numbers.
  • oct () to change the number of Okta.

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